Synthesis of 1,3-dialkyl-4-[(arylmethylidene)amino]glycolurils

Chemistry of Heterocyclic Compounds - A method for the synthesis of 1,3-dialkyl-4-[(arylmethylidene)amino]glycolurils was developed based on nucleophilic substitution of the sulfur atom with the...     

Complexation in Benzo-15-Crown-5–Chloroform–Substituted Acetic Acid Extraction Systems

To study the complexing processes occurring in the extraction systems, the extraction of acetic, propionic (methylacetic), monochloroacetic, dichloroacetic and trichloroacetic acids using benzo-15- crown-5 as an extractant is considered. The extraction isotherms of acids with the pure solvent and 1 M benzo-15-crown-5 in chloroform are determined. The dependences of the distribution ratios of the considered acids on the extractant concentration in the organic phase are presented. Based on the experimental data and the “blank” extraction isotherm equations, the acid: benzo-15-crown-5 ratio in the complexes formed in the extract have been calculated (minus the contribution of extraction with the pure solvent). No complexation of methylacetic acid with benzo-15-crown-5 occurs, and the stability of the complexes of chloro-substituted acetic acids rises in the order acetic acid < monochloroacetic acid < dichloroacetic acid < trichloroacetic acid.     

Peaks of Hydrogen Thermal Desorption: Simulation and Interpretation

Technical Physics - Different models of hydrogen thermal desorption peaks have been analyzed. The model of volume-averaged concentration dynamics with a continuum parameter makes it possible to...     

On the Physics and Atomic Mechanisms of Molecular Hydrogen Intercalation into Graphite Nanofibers

JETP Letters - The fundamental experimental data obtained in [I.O. Bashkin et al., JETP Lett. 79, 226 (2004)] on three states of hydrogen corresponding to physical sorption (state 1), chemisorption...     

On Fundamental Aspects of Solving the Problem of “Super” Storage of Hydrogen in Catalytically Synthetized Graphite Nanofibers

Kinetics and Catalysis - This work considered some fundamental aspects (basics) of solving the long-term (discussed by many researchers for about 25 years) problem of “super” storage...     

Separation of Rare-Earth Elements from Nitrate Solutions by Solvent Extraction Using Mixtures of Methyltri-n-octylammonium Nitrate and Tri-n-butyl Phosphate

The article presents data on the solvent extraction separation of rare-earth elements (REEs), such as La(III), Ce(III), Pr(III), and Nd(III), using synergic mixtures of methyltrioctylammonium nitrate (TOMANO₃) with tri-n-butyl phosphate (TBP) from weakly acidic nitrate solutions. Specifically, experimental results on separation of REEs, for the pair Ce(III)/Pr(III) for quaternary mixtures of REEs (La(III), Ce(III), Pr(III), Nd(III)) and for the pair La(III)/Pr(III) for solutions containing La(III), Pr(III), and Nd(III), are presented. It was shown that effective separation for the pair Ce(III)/Pr(III) from a solution containing 219 g Ce(III)/L, 106 g La(III)/L, 20 g Pr(III)/L, 55 g Nd(III)/L, and 0.1 mol/L HNO₃, was achieved using 56 steps of a multistage, counter-current solvent extraction cascade with scrubbing, at an organic-to-aqueous phase volume ratio (O/A) equal to 2/1 on the extraction section and O/A equal to 4/1 on the scrubbing section, using 3.3 mol/L solutions of the mixture TOMANO₃-TBP with molar ratio 0.15:0.85 in dodecane. Separation for the pair La(III)/Pr(III) could be achieved using a solvent extraction cascade with scrubbing in 32 steps at O/A equal to 2/1 on the extraction section and O/A equal to 2.8/1 on the scrubbing section of the solvent extraction cascade from a solution containing 258 g La(III)/L, 58 g Pr(III)/L, 141 g Nd(III)/L, and 0.1 mol/L HNO₃ with 3.0 mol/L solution of the mixture TOMANO₃-TBP with molar ratio 0.2:0.8 in dodecane.     

Behavior of Na and K in the extraction process of lithium isotope separation

Russian Chemical Bulletin - The extraction behavior of Na and K during lithium isotope separation using benzo-15-crown-5 (B15C5) in chloroform as the extractant was investigated. It was found that...     

Complexation of tetrafluoroboric acid with benzo-15-crown-5

Russian Chemical Bulletin - The extraction of tetrafluoroboric acid from aqueous solutions to a solution of benzo-15-crown-5 (B15С5, 1 mol L-1) in chloroform is shown to occur due to...     

Liquid–liquid extraction of trivalent americium from carbonate and carbonate–peroxide aqueous solutions by methyltrioctylammonium carbonate in toluene

Journal of Radioanalytical and Nuclear Chemistry - Liquid–liquid extraction (LLE) of microamounts of americium(III) from Na2CO3 and Na2CO3–H2O2 aqueous solution using...